Knowledge Update

​New York, Dec 24 (IANS) Researchers have developed a new test that can identify hearing loss or deficits in some individuals considered to have normal or near-normal hearing in traditional tests.

Many adults report difficulties hearing in everyday situations, despite having their physicians or audiologists tell them that the results of their hearing tests are normal or near-normal.

"We now have a validated technique to identify 'hidden' hearing deficits that would likely go undetected with traditional audiograms," said Leslie Bernstein, Professor at University of Connecticut School of Medicine in the US.

Their newly developed hearing test measures a person's ability to detect across-ears (binaural) changes in sounds presented at levels of loudness that are close to those experienced in normal conversations.

The binaural system plays a fundamental and predominant role in the ability to localise sounds, to understand conversation in places such as busy restaurants, and to attend to one of multiple, simultaneous sounds.

The researchers studied 31 adults between ages 30 to 67 with normal or near-normal audiograms.

The results of the study published in the Journal of the Acoustic Society of America showed that listeners who have essentially normal clinical hearing test results may exhibit substantial deficits in binaural processing. 

"Our study shows that our novel binaural hearing test can help early identify vulnerable populations of listeners, and perhaps help determine when critical interventions are warranted," Constantine Trahiotis, Emeritus Professor at University of Connecticut School of Medicine, noted.

Acquired hearing loss from excessive noise exposure has long been known to produce significant, and sometimes debilitating, hearing deficits, Bernstein pointed out.

The new research suggests that hearing loss may be even more widespread than was once thought.

New York, Dec 24 (IANS) If you closely followed the recently concluded US presidential election, you might have already realised what a new study confirms - providing contradictory evidence to change one's political beliefs may actually backfire.

People become more hard-headed in their political beliefs when provided with counter-evidence because the brain may perceive the challenges to political beliefs in the same way it perceives threat and anxiety, the study suggests.

"Political beliefs are like religious beliefs in the respect that both are part of who you are and important for the social circle to which you belong," said lead author Jonas Kaplan from University of Southern California in the US.

"To consider an alternative view, you would have to consider an alternative version of yourself," Kaplan said.

To determine which brain networks respond when someone holds firmly to a belief, the neuroscientists compared whether and how much people change their minds on nonpolitical and political issues when provided counter-evidence.

They discovered that people were more flexible when asked to consider the strength of their belief in nonpolitical statements -- for example, "Albert Einstein was the greatest physicist of the 20th century".

But when it came to reconsidering their political beliefs, such as whether the US should reduce funding for the military, they would not budge.

"I was surprised that people would doubt that Einstein was a great physicist, but this study showed that there are certain realms where we retain flexibility in our beliefs," Kaplan said.

For the study, the neuroscientists recruited 40 people who were self-declared liberals. 

The scientists then examined through functional MRI how their brains responded when their beliefs were challenged.

The study - published in the journal Scientific Reports - found that people who were most resistant to changing their beliefs had more activity in the amygdalae (a pair of almond-shaped areas near the center of the brain) and the insular cortex, compared with people who were more willing to change their minds.

"The activity in these areas, which are important for emotion and decision-making, may relate to how we feel when we encounter evidence against our beliefs," Kaplan said.

"The amygdala in particular is known to be especially involved in perceiving threat and anxiety," Kaplan added. 

"The insular cortex processes feelings from the body, and it is important for detecting the emotional salience of stimuli. That is consistent with the idea that when we feel threatened, anxious or emotional, then we are less likely to change our minds," Kaplan explained.

He also noted that a system in the brain, the Default Mode Network, surged in activity when participants' political beliefs were challenged.

"These areas of the brain have been linked to thinking about who we are, and with the kind of rumination or deep thinking that takes us away from the here and now," Kaplan said.

​New York, Dec 23 (IANS) Children born to women who smoked during their pregnancy were more likely to show signs of kidney damage by the age of three, compared to those born to non-smoking mothers, a research has warned.

The study showed that maternal smoking during pregnancy was one of the risk factors of childhood proteinuria -- abnormal amount of protein in urine -- a sign of kidney disease.

The effects on kidney health were evident in 3-year-old children.

"Maternal smoking during pregnancy is known to be associated with preterm birth, low birth weight, and neonatal asphyxia. The findings from this study suggest an additional adverse effects of maternal smoking during pregnancy," said Koji Kawakami from Kyoto University, in Japan. 

For the study, the team looked for the presence of proteinuria in urinary tests from 44,595 children from pregnancy to three-years of age. 

The results showed that the prevalence rates of proteinuria in children at age three in the maternal smoking groups -- none, past, and current -- were 78.9 per cent, 4.4 per cent and 16.7 per cent, respectively. 

Maternal smoking during pregnancy was associated with a 1.24-times increased risk of child proteinuria compared with no exposure to maternal smoking during pregnancy.

"Prevention of child proteinuria is important since child proteinuria can lead to development of chronic kidney disease in adulthood and ultimately end stage renal disease," Kawakami said.

The findings is forthcoming in the Clinical Journal of the American Society of Nephrology (CJASN). 

New York, Dec 23 (IANS) Exposure to a common plastic compound found in baby bottles and personal care products may increase the risk of pregnant women and lactating mothers developing negative behavioural changes and impairment in brain regions, researchers have warned.

The study, conducted in mice, showed that the exposure to bisphenol S (BPS) -- a replacement chemical for Bisphenol A (BPA) -- impaired the maternal care of pups, including mothers' ability to adjust to the needs of their young during early development. 

"BPS affects maternal behaviour as well as maternally relevant neural correlates," said Mary Catanese, doctoral student at the University of Massachusetts - Amherst. 

The effects differ based on dose, postpartum period and generational timing of exposure, Catanese said.

Further, BPS exposure was found to increase the infanticide thoughts in a brain region sensitive to estrogen or estrogen-mimicking chemicals as well as important in maternal behaviour in mice. 

"Although these same effects were not seen at the higher dose, more than 10 per cent of females exposed to two microgram BPS/kg per day either killed their pups or provided such poor instrumental maternal care that one or more pups needed to be euthanised. 

While not statistically significant, the neglect and poor maternal care we observed were striking," explained Laura Vandenberg, assistant professor at the University of Massachusetts.

In addition, BPS exposure may also impair a mother to adjust to the changing needs of her pups, the researchers observed.

BPS-exposed mothers showed significantly shorter latency to retrieve their first pup and significantly shorter latency to retrieve their entire litter, which may not represent improved care but instead "may indicate hyperactivity, compulsivity-like behaviour, heightened stress response to scattered pups, or a displaced form of retrieval," Vandenberg noted.

The details of the study appeared in the journal Endocrinology.

New York, Dec 23 (IANS) You can literally lose sleep over discrimination as a new study has found that people who perceive more unfairness in daily life have higher rates of sleep problems.

"Discrimination is an important factor associated with sleep measures in middle-aged adults," according to the study by Sherry Owens of West Virginia University in the US, and colleagues. 

The research included 441 adults from a study of health and well-being in middle age and beyond (the MIDUS Study). The participants' average age was 47 years. 

Participants wore an activity monitor device for one week to gather data on objective sleep measures -- for example, sleep efficiency, calculated as the percentage of time spent in bed that the person was asleep. 

They also completed subjective sleep ratings -- for example, how often they had sleep problems.

Perceived experiences of discrimination were assessed using a validated "Everyday Discrimination Scale." 

For example, participants were asked how often they were treated with less courtesy or respect than others, or how often they were insulted or harassed.

Participants who perceived more discrimination had increased sleep problems, according to the study published in Psychosomatic Medicine: Journal of Biobehavioral Medicine.

Higher discrimination scores were associated with 12 per cent higher odds of poor sleep efficiency and a nine percent increase in the odds of poor sleep quality. 

Discrimination was also related to (objective) time spent awake after falling asleep and (subjective) overall sleep difficulties.

While poor sleep has previously been linked to higher perceived discrimination, the researchers said that the new study is the first to look at how discrimination affects both objective and subjective sleep measures.

"The findings support the model that discrimination acts as a stressor than can disrupt subjective and objective sleep," the study said.

New York, Dec 23 (IANS) Researchers have developed a new tattoo ink that glows only under certain light conditions and disappears later. It can better help in surgical treatment of patients with a form of skin cancer much more than the commercially available tattoo pigments.

Tattoos may not be just for body art, but are also used by the medical community for precisely demarcating future treatment landmarks. 

This is especially important for identifying biopsy sites of nonmelanoma skin cancer (NMSC) patients as they typically have to wait up to three months between a biopsy confirming their condition and treatment. 

However, the commercially available tattoo pigments inks can cause discomfort and inflammation.

The new ink developed by researchers led by Kai Chen University of Southern California is time-limited. Under ambient lighting, the nanoparticles are invisible, which would avoid unwanted markings in a patient's skin, and is a safer, more patient-friendly option. 

Testing in mice showed that tattoos created with these nanoparticles did not cause inflammation and lasted for three months. 

The study was published in the journal ACS Nano.

​London, Dec 23 (IANS) In a large human trial led by the World Health Organisation (WHO), an experimental Ebola vaccine was found highly protective against the deadly virus, promising an effective weapon against any future outbreak.

The vaccine is the first to prevent infection from one of the most lethal known pathogens, according to the results published in The Lancet journal. 

"While these compelling results come too late for those who lost their lives during West Africa's Ebola epidemic, they show that when the next Ebola outbreak hits, we will not be defenceless," said Marie-Paule Kieny, WHO's Assistant Director-General for Health Systems and Innovation, and the study's lead author.

In the most recent Ebola outbreak in West Africa that started in late 2013, more than 11,000 people lost their lives. The WHO removed the global emergency tag for the disease early this year.

The vaccine, called rVSV-ZEBOV, was studied in a trial involving 11,841 people in Guinea during 2015. 

Among the 5,837 people who received the vaccine, no Ebola cases were recorded 10 days or more after vaccination. 

In comparison, there were 23 cases 10 days or more after vaccination among those who did not receive the vaccine.

The trial was led by the World Health Organization, together with Guinea's Ministry of Health and other international partners.

The vaccine's manufacturer, Merck, Sharpe & Dohme, this year received Breakthrough Therapy Designation from the United States Food and Drug Administration and PRIME status from the European Medicines Agency, enabling faster regulatory review of the vaccine once it is submitted.

Since Ebola virus was first identified in 1976, sporadic outbreaks have been reported in Africa. 

But the 2013-2016 West African Ebola outbreak, which resulted in more than 11,300 deaths, highlighted the need for a vaccine.

The trial took place in the coastal region of Basse-Guinée, the area of Guinea still experiencing new Ebola cases when the trial started in 2015. 

To assess safety, people who received the vaccine were observed for 30 minutes after vaccination, and at repeated home visits up to 12 weeks later. 

Approximately half reported mild symptoms soon after vaccination, including headache, fatigue and muscle pain but recovered within days without long-term effects. 

Two serious adverse events were judged to be related to vaccination (a febrile reaction and one anaphylaxis) and one was judged to be possibly related (influenza-like illness). 

All three recovered without any long term effects, the study reported.

London, Dec 22 (IANS) Researchers have shown that instead of expensive equipment, smartphones can be used to make movies of living cells and observe their response to different treatments.

Live imaging of cells is a very powerful tool for the study of cells, to learn about how cells respond to different treatments such as drugs or toxins.

The study published in the journal PLOS ONE showed that a simple smartphone can replace expensive equipment used for the process.

"The technology presented here can readily be adapted and modified according to the specific need of researchers, at a low cost," said Johan Kreuger from Uppsala University in Sweden.

"Indeed, in the future, it will be much more common that scientists create and modify their own research equipment, and this should greatly propel technology development," Kreuger said.

In the present study, old standard inverted microscopes that are very abundant at universities and hospitals were upgraded to high quality live imaging stations using a few 3D-printed parts, off-the-shelf electronics, and a smartphone. 

It was shown that the resultant upgraded systems provided excellent cell culture conditions and enabled high-resolution imaging of living cells.

London, Dec 22 (IANS) British researchers have developed a breakthrough technique that uses sound rather than light to see inside live cells, a finding that has potential application in stem-cell transplants and cancer diagnosis.

The new sub-optical phonon (sound) imaging technique uses shorter-than-optical wavelengths of sound and could even rival the optical super-resolution techniques. 

It provides invaluable information about the structure, mechanical properties and behaviour of individual living cells at a scale not achieved before.

"Like ultrasound on the body, ultrasound in the cells causes no damage and requires no toxic chemicals to work. Because of this, we can see inside cells that one day might be put back into the body, for instance as stem-cell transplants," said Matt Clark, Professor at the University of Nottingham in Britain.

In optical microscopy, which uses light (photons), the size of the smallest object you can see or the resolution is limited by the wavelength.

For biological specimens, the wavelength cannot go smaller than that of blue light because the energy carried on photons of light in the ultraviolet and shorter wavelengths is so high it can destroy the bonds that hold biological molecules together damaging the cells.

Also, the fluorescent dyes used in optical super-resolution imaging are often toxic and it requires huge amounts of light and time to observe and reconstruct an image which is damaging to cells.

However, sound does not have a high-energy payload. This uses smaller wavelengths and enables to see smaller things and get higher resolution images without damaging the cell biology, the researchers noted.

The study is published in the journal Scientific Reports.

New York, Dec 22 (IANS) A distinctive neural signature found in the brains of people with dyslexia may explain why they have difficulty in learning to read and adapting to sensory inputs, according to a new study.

The brain typically adapts rapidly to sensory input, such as the sound of a person's voice or images of faces and objects, as a way to make processing more efficient. 

But, the study found that for individuals with dyslexia, the adaptation was on average nearly half.

In dyslexic people, the brain has a diminished ability to acclimate to a repeated input -- a trait known as neural adaptation. 

For example, when dyslexic students see the same word repeatedly, brain regions involved in reading do not show the same adaptation seen in typical readers.

This suggests that the brain's plasticity, which underpins its ability to learn new things, is reduced, said John Gabrieli, professor at Massachusetts Institute of Technology (MIT) in the US.

"It's a difference in the brain that's not about reading per se, but it's a difference in perceptual learning that's pretty broad," Gabrieli added.

For the study, the team used MRI technique where the brains of young adults with and without reading difficulties were scanned as they listened to a series of words read by either four different speakers or a single speaker.

The results revealed that the dyslexic participants showed much less adaptation to hearing words said by a single speaker.

Further, for dyslexics the brain activity remained high while listening to a consistent voice and not to multiple voices, suggesting that they did not adapt as much. 

Again, when researchers looked at adaptation to visual stimuli, they saw much less adaptation in participants with dyslexia.

"This suggests that adaptation deficits in dyslexia are general, across the whole brain," noted Tyler Perrachione, assistant professor at Boston University in Massachusetts, US. 

The study appears in the journal Neuron.